1. Field of the Invention
This invention relates to closures, and is more particularly concerned with closures for large openings such as provided in aircraft hangers.
2. Description of the Prior Art
In U.S. Pat. No. 3,211,211 Wilbur Youngs discloses a closure for an aircraft hanger in which an elongate tube is connected to the bottom marginal edge of and takes up and pays out a curtain which has its top marginal edge connected to a header of the opening. An electric motor, with a gear reduction unit, coacts between at least one end of the tube and a side wall of the opening to cause rotation of the tube and take up and pay out of the curtain.
Other mechanisms are well known in the art, particularly in the art of stage curtains and the like, wherein electric motor mechanisms are mounted within a tube connected to the bottom marginal edge of a curtain.
There is a multitude of other art concerned with the sealing of bottom and side marginal edges of a curtain which is lowered to a closed position. These devices, however, usually involve manually operated closing and locking mechanisms.